Grinding attachment for twist drills



' Feb. 12, 1946. H, B WMAN 2,394,839

. GRINDING ATTACHMENT FOR TWIST DRILLS Filed July 21, 1944 1 2 sheets-sheet 1 Inventor I I 4/ I My Atto meys Feb. 12,1946. c; BOWMAN 2,394,839

- GRINDING ATTACHMENT FOR TWIST DRILLS Filed July 21, 1944 2 Sheets-$heet 2 Inventor (AarZesfirZan Zazbman M Patented Feb. 12, 1946 S PATENT OFFICE GRINDING ug HMENT FOR TWIST C RILL Charles Harlan Bowman, Madison, Wis. Application July 21, 1944, Serial No. 545,964

2 Claims.

The presentinvention relates to new and useful improvements in devices for holding twist drills in position while the same is being sharpened by means of a grinding or abrasive wheel.

An important object of the present invention is to provide a holder for the drill adapted for attaching to a work bench and embodying means for clamping and holding the drill in a manner to permit the partial rotation thereof while the cutting end of the drill is held against the grinding wheel.

A further important object is to provide a rockably mounted support for the drill holder by means of which the drill may be partially rotated during the grinding or sharpening thereof and in which the drill holder may be removed from its support and placed in a reversed position therein so that the entire cutting end of the drill may be sharpened without removing the drill from the holder.

A still further object is to provide a device of this character of simple and practical construction, which is eflicient and reliable in performance, relatively inexpensive to manufacture and otherwise well adapted for the purposes for which the same is intended.

Other objects and advantages reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure 1 is a perspective view.

Figure 2 is a transverse sectional view through the attaching plate.

Figure 3 is a vertical sectional view through the bit holder and showing the rocking support therefor.

Figure 4 is a transverse sectional view through the clamping member for the bit.

Figure 5 is a fragmentary perspective view of the upper end of the front support for the bit, and

Figure 6 is a fragmentary group perspective view of the attaching plate and base of the support.

Referring now to the drawings wherein for the purpose of illustration I have disclosed a preferred embodiment of the invention the numeral 5 designates an attaching plate generally which is preferably composed of a pair of spaced parallel elongated plates 9 connected at their end portions by upper and lower cross plates 1 and 8 having openings 9 therein adapted for receiving bolts or screws for attaching the plate to a work bench.

"The cross plates 1 and 8 at one end of the attaching plate are provided with a wing bolt ID for securing the base I I in adjusted position between the cross plates 1 and 8 and in longitudinally adjusted position between the plates 6. The base is formed of strap metal and is provided intermediate its ends with an upstanding support l2 also formed of strap metal bent upon itself and having its ends welded or otherwise secured to the upper surface of the base. The upper end of the support [2 is formed with a notch l3 constituting a saddle in which a twist drill I 4 is seated, the drill projecting from one end of a drill holder shown generally at l5.

Rising from the rear end of the base II is a support It having its upper end curved horizontally as shown at I! and terminating in a bearing [8 having a pin l9 secured therein.

A U-shaped hanger 20 formed at one end rockably mounted on the pin [9.

The drill holder is formed of strap metal and bent intermediate its ends to form a pair of spaced parallel members 22 and 23 connected to each other at one end and having an opening 24 at said connected end while the free end of the member 22 i formed with a transversely extending flange 25 which closes the other end of the holder l5. The flange 25 is also formed with an opening 26 through which the drill l4 projects.

The drill is secured in position in the holder l5 by means of a pair of clamping blocks 21 and 28 having V-shaped channels 29 in their opposed faces for receiving the shank of the drill, the blocks being positioned between the members 22 and 23 of the holder and secured in position therein by means of a clamping member 29 of open frame construction slidably mounted on the holder l5 and having a bolt 30 threaded through one end by means of a wing head 3| for forcing the members 22 and 23 against the opposite sides of the clamping blocks 21 and 28.

One end of the holder I5 is supported in the U- shaped hanger 20 while the bit I4 is supported in the saddle 13 of the front support I2 whereby the holder l5 may be rocked in an oscillating movement as indicated by the arrows in Figure 1 of the drawings.

Th'e hanger 20 is supported in a horizontal plane above the saddle I3 whereby the holder [5 will have a tendency to slide forwardly for contacting the end of the drill I 4 with a grinding or also has a bearing 2| abrasive wheel (not shown) in a manner for grinding or sharpening the drill.

The holder I5 with the drill clamped in position therein may belifted bodily from the hanger 20 and the front support l2 so that the position of the drill and holder may be reversed, when desired.

It is believed that the details of construction and manner of use of the device will be readily understood from the foreging without further detailed explanation.

Having described the claimed as new is:

1. A drill bit sharpener comprising an'attaching plate, a base secured to said plate, a, pair of supports rising from said base, one being provided with a saddle at its upper end for receivinvention, What is ing a drill bit therein and the other having a laterally extending upper end, a drill bit holder comprising elongated side member spaced apart laterally and connected at one end for flexing toward each other into clamping relation, one of said side members having a right angled flange at its other end apertured for the extension of the drill bit therethrough' into said saddle, a pair of opposed clamping blocks between said side members adapted to receive the drill bit therebetween and be moved into clamping relation by such flexing or said side members, means to flex said side members toward each other, and suspension means for swingably connecting said holder to the laterally extending end of said other support in underslung position relative thereto.

2. A drill bit sharpener comprising an attaching plate, a base secured to said plate, a pair of supports rising from said base, one being provided with a saddle at its upper end for receiving a drill bit therein and the other having a laterally extending upper end, a drill bit holder comprising elongated side members spaced apart laterally and connected at one end for flexing toward each other into clamping relation, one of said side members having a right angled flange at its other end apertured for the extension of the drill bit therethrough into said saddle, a pair of opposed clamping blocks between said side members adapted to receive the drill bit therebetween and be moved into clamping relation by such flexing of said side members, means to flex said side members toward each other, and suspension means for swingably connecting aid holder to the laterally extending end of said other support in underslung position relative thereto comprisinga U-shaped hanger straddling said holder.

CHARLES HARLAN BOWMAN. 

